Automatic sample changer for positioning a plurality of pellets in an X-ray analyzer

ABSTRACT

A sample changer for sequentially locating samples for relative angular movement with respect to an X-ray source and detector for diffraction analysis includes first and second pneumatically controlled sample positioning cylinders, each carried upon a plate having a sample locating hole to a base upon which the samples are sequentially positioned. A slot along the length of the plate intersects the hole to provide a path along which the samples are moved or rolled after testing. The second pneumatic cylinder controls an ejector plate which rides in the slot and is moved by the pneumatic cylinder across the hole to eject the sample from the hole into the slot. A pneumatic switching network provides sequentially applied and exhausted controlled pneumatic pressure to the first and second pneumatic cylinders for operation.

[451 Nov. 18, 1975 United States Patent [191 Roe [ AUTOMATIC SAMPLE CHANGER FOR POSITIONING A PLURALITY OF PELLETS Primary ExaminerStanley Tollberg IN AN X-RAY ANALYZER Attorney, Agent, or Firm-Robert M. Betz [75] Inventor:

[ 7] ABSTRACT A sample changer for sequentially locating samples for relative angular movement with respect to an X-ray Glenn D; Roe, Dallas, Tex.

Assignee: Atlantic Richfield Company, Los

Angeles, Calif.

Jan. 15, 1973 [22] Filed; source and detector for diffraction analysis includes first and second pneumatically controlled sample posi- PP No.2 323,730 tioning cylinders, each carried upon a plate having a sample locating hole to a base upon which the samples are sequentially positioned. A slot along the length of the plate intersects the hole to provide a path along which the samples are moved or rolled after testing.

[58] Field of Search The second pneumatic cylinder controls an ejector plate which rides in the slot and is moved by the pneumatic cylinder across the hole to eject the sample from the hole into the slot. A pneumatic switching network provides sequentially applied and exhausted controlled pneumatic pressure to the first and second pneumatic cylindersfor operation.

221/232 X 221/278 X 221/279 X 221 /279 X 7 Claims, 1 Drawing Figure 2,608,002 Bielstein 3,028,996 4/1962 3 130 865 4/1964 3,232,215 2/1966 VALVE VO LTAGE AND TABLE CONTROL R E D R w E R 0 T M US. Patent Nov. 18, 1975 AUTOMATIC SAMPLE CHANGER FOR POSITIONING A PLURALITY OF PELLETS I "AN" lytical applications, for example, in analyzing rock and soilcompo'sitions to determine'the' element or mineral content 1n soil cores, cuttingfor samples fr'omja particular area. In some diffraction equipment presently used in such analyses, a sample of the 'material isrnade into a paste and smeared or applied onto"a"glassslide,'much like the familiar photographic etransparancy slide, 'which is located at a fixed position withrespect to a columnated, essentially monochromatic' X ray beam directed onto the sample. The sampleis tlien rotated with respect to the beam, and the :diffracte'd cornponents of the beam are detected andplot ted' as angular rotation of the sample versus the detected Xray intencomponent.

f Because a largenurnber of oftenaredesiredi to be'analy'zed, usually in a specific sequence, automatic sample changersha've been proposed in which a number of samples are automatically"sequenced-for analysis, to produce a continuous output graph, magnetic tape, orjthe like, or other "sical indicia of the diffraction pattern produced the respective samples. One such sampl'e sequencer is 'i n 'th'e form' of the familiar photographic slide transparne changer by which' 'the samples on such glassslide mourits intoand out of analyzing location. In such slide clian'gers, however, the samples are fragile and require cumbersome fabrica-"' tion methods. Also, at leastone'slides'urface'is ofrough upon a machined aluminum base for ease of handling.

texture resulting from the inheriit'naturbf the i and soil to be analyzed, resulting in mechanical moving and sliding v problems requiring relatively fragile and complicated rnovi ng,mechanisrnst Another sample changer form is that advanced by Glenn D. Roe, applicant herein, and Carl 'A. Young-' man, disclosed in U.S Pat. 3 52 7,9142, in "which the samples are; configured into circular or plate like pellets and aligned on "edge in an inclined loading ramp which gravity feeds the pellets sequentially to a sample holder. The pellets rollone at a time into a channel in the sample holder having an Offset in its path atthe point at which the pellets are toibe located for analysis,

The thickness or width dimension, 'however', of the sample is of interest in the use of the inclined ramp, above described, for example, and a certain degree of quality control is required. If, for instance, the sample width of the individual pellets is too large, they may encounter difficulty in traversing curves in the inclined entrance ramp. On the other hand, if the sample width is too small, the subsequently disposed samples along the route of the ramp may tend to pass the preceding sample and jam up the sample procession.

BRIEF DESCRIPTION OF THE INVENTION 'In light of the above, it is, therefore, an object. of the invention to present a sample changer for automatically sequentially positioning a plurality of pellets in an X-ray diffraction analyzer.

It is another object of the invention to present an automatic sample changer in which the relative importance of the sample size is reduced.

It is another object of the invention to provide an automatic sample changer for more rapid sample workmg. I

It is anotherobject of the invention to present an automatic, sample changer in which the particular alignment of the samples is not critical. I Y It is still another object of the invention to provide an automatic sample changer which is of relatively simple design, rugged,.and relatively manintenance free.

These and other objects, features, and advantages will become apparentto those skilled in the art from thefollowing'detailed description when read in conjunction with the accompanying drawings appended claims.

--ln accordance witha preferred embodiment of the invention, an apparatus for sequentially locating samples for angular movement-with respect to an X-ray source and detector is presented. The apparatus includes a base and an adjacent plate having a sample discharge slot'formed along its length and a sample inlet pneumatic cylinder is also carried by the plate and in- "cludes a piston rod connected to the piston within the the offset acting to stop the fOrWard prQgIQSS Of the pellet parade. An electrically operated,solenoidpushes the particular pellet in the offset back onto the path, but temporarily constrains. it against a locating base adjacent the offset during exposure to the Xrray beam through a desired angular rotation. The pellet .is then released to continue its journey through aninclined discharge ramp; the nextpellet rolls into position in the path offset, and the process is repeated.

The pellets, themselves, formed into generally cylin-- drical shape by a hydraulic press or the like, for use in.- the devices heretofore advanced, are ordinarily placed second pneumatic cylinder extending outside the cylinder/An ejector plate is connected to the piston rod of a second pneumatic cylinder, and is movable within the discharge slot across the hole to eject the sample thereat. Finally, means for controllably applying air pressure to the first and second cylinders is provided whereby after each sample is tested, the second pneumatic cylinder is actuated to eject the sample, and the first pneumatic cylinder is subsequently actuated to move the next sample to be tested into position within the hole.

BRIEF DESCRIPTION OF THE DRAWING DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The sample changer, in accordance with the invention, is illustrated in the sole accompanying drawing, and is intended for use primarily in connection with X-ray diffraction equipment. The X-ray diffraction equipment illustrated, an example of the many with which the changer can be used, includes a base assembly including a platform 11 upon which a turntable 12 is rotatably mounted. The turntable 12 is driven by a motor, not shown. to rotate in the manner below described. An X-ray source 13 is mounted at a known angular location with respect to the turntable l2, and an K-ray detector 14 is mounted to the turntable 12 rlmount not shown). Upon the turntable 12, a post or base 16 is mounted at an angle at which the X-rays from the X-ray source 13 can impinge upon a sample disposed adjacent the base 16 upon its face 17 whereby the diffracted X-rays can be detected by the detector 14 and recorded (recorder not shown).

In operation, the turntable 12 is moved from a first predetermined position to a second while the X-ray source 13 is in continuous operation, carrying the IK-ray detector 14. The sample to be tested is positioned adjacent a base 16 which is geared to rotate at one-half the speed of the turntable 12, to rotate the sample with respect to the X-ray source 13 whereby the diffracted X-rays can be detected and recorded for subsequent analysis. The angular rotation can be controlled, for example, by adjustable protrusions 18 and 19 carried by and overhanging the edge of the turntable 12 to engage a switch 20 mounted on the table 11. Thus, beginning from an angular position with the protrusion 18, adjacent the switch 20, the table is rotated, as shown by the arrow, until the protrusion 19 engages the switch 20, whereupon the rotation is reversed and the table moved back to the beginning position.

To sequence a plurality of samples for analysis, a source assembly 28, a positioning assembly 15, and an ejector assembly 40 are provided, all carried upon the base 16. A plate 23 of the positioning assembly 15 has a slot 24 along its length, and an intersecting hole or window 25 located adjacent the base 16 into which the samples 29 are introduced. A wire stop 26 is located next to the window 25 to prevent samples moved into the window 25 from prematurely or undesirably rolling down the exit chute 27.

A supply cylinder 22 of the source assembly 28 is threadably engaged within the window 25 in the plate .23 (threads not shown). As illustrated in the cutaway portion, a stack of samples 29 are received within the supply cylinder 22 and are moved forward by a piston .31 driven by air from air line 33, in a manner below described. A micro-switch is mounted by arm 36 onto the cylinder 22 to engage a washer 37 or like protrusion at the end of a rod 39 attached to the piston 31 and extending through end cap 30, to provide an automatic stop after the last one of samples 29 has been analyzed.

At this juncture, it should be pointed out that although the samples 29 are described and illustrated as being of cylindrical or plate shape, they can be of any shape, such as square or oval, with appropriate accommodating modifications to the supply cylinder 22 and the window 25, as will be apparent to those skilled in the art.

.An ejector cylinder 41 of ejector assembly is mounted onto the plate 23, such as by a mounting bar 4 42, shown. A piston 43 within the cylinder 41 is normally biased by springs 44 and 45 away from the direction the samples 29 are discharged'from the window 25. The springs are conveniently mounted onto piston rods 46 and 47, respectively, which extend through holes in the ends 50 of the cylinder 41. To enable the piston to move under the influence of the air pressure supplied by an air line 48, an exhaust hole 49 is provided in the end 50 of the cylinder 24. i

A sample ejector plate 52 is mounted by an arm 53 to the piston rod 47. The plate 52 fits and rides within the slot 24 of the plate 23 and is normally in a position slightly back from the window 25. The end of the plate 52 can be formed to accommodate the shape of the sample which the end engages, such as the semicircular shape illustrated, for efficient operation.

The air lines 48 and 33 of the ejector and supply cylinders 41 and 22, respectively, are connected to a pneumatic control network 60, which provides the respective air pressures for operation. In the drawing, the continuations of the respective air lines 48 and 33 are shown by dotted lines, and are denoted, respectively, by encircled numerals 1 and 2. An air source 61, which can be a bottled air supply, as shown, or other convenient source of air or usable gas, supplies air (or gas) to an electrically actuated pneumatic valve 62 of the type which switches the input between two outputs 63 and 67. Thus, in the embodiment illustrated, the unenergized valve 62 applies the air pressure of air source 61 to the output line 67 and, when energized, to the output line 63. The valve 62 is electrically controlled by voltage control 66, which, in turn, is connected to the switch 20 to the responsive to the angular position of the turntable 11, as above described.

The output line 63 is connected to the line 48 of the ejector cylinder 41 through a manually controllable valve 64, to allow adjustment of the air pressure ap plied, and through a check valve 65 to allow rapid pressure exhaust, as below described. On the other side, the output line 67 from the valve 62 is connected to the Iine 33 to provide air pressure to the source cylinder 22. Like the network to the ejector cylinder 41, a manual control valve 68 is provided, and, in parallel therewith, a check valve 69 is provided to facilitate rapid exhaust.

At least one, or a plurality of exhaust lines, such asillustrated exhaust lines 70 and 71, can also be provided from valve 62, as shown. The exhaust line 70 is, for instance, connected to the output line 67 in the energized state and the line 71 is connected to the output line 63 in the unenergized state of the valve 62. A Y or T connection 73 can be also provided, as shown, in an exhaust line, such as line 71, by which a line 74 can be run to exit adjacent the window 25 (line location not illustrated) in the plate 23 to direct exhausted air to the window and chute to blow dust and other particles from the sample path.

In operation, movement of the turntable 11 is begun from the protrusion 18, detected by the switch 20. As the turntable begins to rotate moving the protrusion 19 in the direction of the arrow toward the switch 20, the pneumatic valve 62 is in its normal or unenergized state. Air pressure from air source 61 is thus applied via tubes 67 and 33 to behind piston 31 of the supply cylinder 22, and no pressure is applied to the ejector cylinder 41, line 48 communicating through check valve 65, line 63 and valve 62 with exhaust line 71. The piston 31, therefore, is moved by the air pressure within the cylindeer 22 in the direction of the base 16 to move one of samples 29 through the window 25. As the turntable rotates, the X-rays from the source 13 are impinged upon the sample 29, detected, and recorded, as above described.

When the turntable fulfills the desired angular rotation, the switch 20 is tripped by the protrusion 19, thereby applying a voltage from source 66 to the pneumatic valve 62, simultaneously reversing the direction of rotation of turntable 12 to drive toward the starting position. The air from air source 61 is then directed into the ejector cylinder 41 via tubes 63 and 48. Meanwhile, the air pressure within the source cylinder 22 is rapidly exhausted through line 33, check valve 69, line 67, valve 62, and the exhaust tube 70.

As the air-pressure is applied to the ejector cylinder 41, the ejector plate 52 is moved against the spring bias of springs 44 and 45 at least partially or entirely across the window 25 to move the sample located therein over the wire stop 26 to discharge the sample through discharge chute 27 into a receiving container, not shown.

As the turntable rotates to its original position, the valve 62 will again be unenergized, and the air pressure within the ejector cylinder 41 will be exhausted. The exhaust air from within ejector cylinder 22 is partially diverted by T 73 through tube 74 to blow out dust and other particles from chute 23, as above explained, prior to the introduction of the next sample into the window 25.

The manual valves 64 and 68 are adjustable to permit the air pressure from source 61 to be applied to their respective sample control cylinders at a relatively slow rate. Thus, as described, when the table 12 has reached its end rotation at protrusion 19 and begins its travel back towards protrusion 18, the pneumatic valve 62 becomes unenergized. The ejector plate 52 is rapidly moved back from the hole 25 to its neutral position because of the rapid exhaust of the pressure through check valve 65, and the influence of the springs 44 and 45. The pressure to the source cylinder 31, however, is applied slowly, the precise rate being controlled by valve 68, to enable the plate 52 to move completely out of the way without binding upon the sample subsequently moved into window 25. This has an incidental advantage in allowing the dust from a preceding sample to be blown clear from the window 25 and chute 24 by exhaust air through the tube 74 prior to the introduction of the next sample into the window. Likewise, when the table 11 reaches protrusion 18, the pneumatic valve 62 is energized, and pressure is applied to behind piston 43 at a rate determined according to adjustable manual valve 64. Thus, after the pressure has been exhausted from behind piston 31 of cylinder 22, and, therefore, no pressure on the samples 29 in the direction of the base 16 is applied, the plate 52 will then be slowly moved to overcome the bias of springs 44 and 45 to efficiently eject the sample in the hole 25.

If desired, the sample analyzer can be arranged for continuous measurement; for example, by causing the sample being measured to eject upon termination of one direction of rotation of the turntable 12 between protrusions 18 and 19. At that terminal point, for instance, a subsequent sample can be inserted and analyzed in reverse direction as the turntable 12 is moved to its original position.

Although the invention has been described and illustrated with a certain degree of particularity, it is understood that the present disclosure is made by way of illustration only and that numerous changes in the details of construction and the combination and arrangement of parts may be resorted without departing from the spirit and scope of the invention as hereinafter claimed.

What is claimed is:

1. Apparatus for sequencing samples comprising:

a sample positioning plate mountable adjacent a base, having a slot along a side adjacent the base and a hole extending to the slot from an opposite side;

a first pneumatic cylinder carried upon said sample positioning plate opening to within the hole therein, in which the samples are loaded, having a piston for sequentially moving the samples through the hole;

a second pneumatic cylinder carried upon said sample positioning plate having a piston therewithin;

ejector means connected to the piston of said second pneumatic cylinder, moveable within the slot at least partially across the hole of said sample positioning plate to eject the sample thereat, along the slot; and

means for controllably applying air pressure to said first and second cylinders.

2. The apparatus of claim 1 wherein said ejector means comprises an ejector plate which rides in the slot of said sample positioning plate, and a piston rod attached to the piston of said second pneumatic cylinder, said ejector plate being connected to said piston rod.

3. The apparatus of claim 2 wherein said means for applying air pressure comprises means for sequentially slowly applying and rapidly exhausting air pressure to said first and second pneumatic cylinders.

4. The apparatus of claim 3 wherein said means for sequentially slowly applying and rapidly exhausting air pressure comprises two air lines connected respectively to said first and second pneumatic cylinders; an air valve for connecting an air source between a selected one of said two air lines and having at least one exhuast outlet switchable between the non-connected of said two air lines; controllable valve means in each of said two lines; and check valves connected in parallel with each of said controllable valve means.

5. The apparatus of claim 4 further comprising means within the slot in said sample positioning plate partially restricting the ejection path of said samples for preventing samples moved through said hole from moving prematurely out of position.

6. The apparatus of claim 5 wherein said means for retaining the samples in position comprises a wire adjacent said hole opposite said ejector means.

7. The apparatus of claim 6 wherein said second pneumatic cylinder comprises a piston rod for connection to said ejector means and means for biasing said piston rod whereby said ejector plate is away from the hole in said sample positioning plate. 

1. Apparatus for sequencing samples comprising: a sample positioning plate mountable adjacent a base, having a slot along a side adjacent the base and a hole extending to the slot from an opposite side; a first pneumatic cylinder carried upon said sample positioning plate opening to within the hole therein, in which the samples are loaded, having a piston for sequentially moving the samples through the hole; a second pneumatic cylinder carried upon said sample positioning plate having a piston therewithin; ejector means connected to the piston of said second pneumatic cylinder, moveable within the slot at least partially across the hole of said sample positioning plate to eject the sample thereat, along the slot; and means for controllably applying air pressure to said first and second cylinders.
 2. The apparatus of claim 1 wherein said ejector means comprises an ejector plate which rides in the slot of said sample positioning plate, and a piston rod attached to the piston of said second pneumatic cylinder, said ejector plate being connected to said piston rod.
 3. The apparatus of claim 2 wherein said means for applying air pressure comprises means for sequentially slowly applying and rapidly exhausting air pressure to said first and second pneumatic cylinders.
 4. The apparatus of claim 3 wherein said means for sequentially slowly applying and rapidly exhausting air pressure comprises two air lines connected respectively to said first and second pneumatic cylinders; an air valve for connecting an air source between a selected one of said two air lines and having at least one exhuast outlet switchable between the non-connected of said two air lines; controllable valve means in each of said two lines; and check valves connected in parallel with each of said controllable valve means.
 5. The apparatus of claim 4 further comprising means within the slot in said sample positioning plate partially restricting the ejection path of said samples for preventing samples moved through said hole from moving prematurely out of position.
 6. The apparatus of claim 5 wherein said means for retaining the samples in position comprises a wire adjacent said hole opposite said ejector means.
 7. The apparatus of claim 6 wherein said second pneumatic cylinder comprises a piston rod for connection to said ejector means and means for biasing said piston rod whereby said ejector plate is away from the hole in said sample positioning plate. 